Merge "docs: nxp soc-lx2160a based platforms" into integration

5 files changed, 731 insertions, 0 deletions

diff --git a/docs/plat/index.rst b/docs/plat/index.rst
index 4dc9ecd23..5848005ba 100644
--- a/docs/plat/index.rst
+++ b/docs/plat/index.rst
@@ -27,6 +27,7 @@ Platform Ports
    imx8
    imx8m
    ls1043a
+   nxp/index
    poplar
    qemu
    qemu-sbsa
diff --git a/docs/plat/nxp/index.rst b/docs/plat/nxp/index.rst
new file mode 100644
index 000000000..85468877b
--- /dev/null
+++ b/docs/plat/nxp/index.rst
@@ -0,0 +1,17 @@
+NXP Reference Development Platforms
+===================================
+
+.. toctree::
+   :maxdepth: 1
+   :caption: Contents
+
+   nxp-layerscape
+   nxp-ls-fuse-prov
+   nxp-ls-tbbr
+
+This chapter holds documentation related to NXP reference development platforms.
+It includes details on image flashing, fuse provisioning and trusted board boot-up.
+
+--------------
+
+*Copyright (c) 2021, NXP Limited. All rights reserved.*
diff --git a/docs/plat/nxp/nxp-layerscape.rst b/docs/plat/nxp/nxp-layerscape.rst
new file mode 100644
index 000000000..3d983542f
--- /dev/null
+++ b/docs/plat/nxp/nxp-layerscape.rst
@@ -0,0 +1,232 @@
+NXP SoCs - Overview
+=====================
+.. section-numbering::
+    :suffix: .
+
+The QorIQ family of ARM based SoCs that are supported on TF-A are:
+
+1. LX2160ARDB:
+        Platform Name:
+
+        a. lx2160ardb (Board details can be fetched from the link: `lx2160ardb`_)
+
+
+Table of supported boot-modes by each platform & platform that needs FIP-DDR:
+-----------------------------------------------------------------------------
+
++---+-----------------+-------+--------+-------+-------+-------+-------------+--------------+-----------------+
+|   |     BOOT_MODE-->|  sd   |  qspi  |  nor  | nand  | emmc  | flexspi_nor | flexspi_nand | fip_ddr needed  |
+|   |                 |       |        |       |       |       |             |              |                 |
+|   |     PLAT        |       |        |       |       |       |             |              |                 |
++===+=================+=======+========+=======+=======+=======+=============+==============+=================+
+| 1.| lx2160ardb      |  yes  |        |       |       |  yes  |   yes       |              |       yes       |
++---+-----------------+-------+--------+-------+-------+-------+-------------+--------------+-----------------+
+
+Boot Sequence
+-------------
+::
+
++                           Secure World        |     Normal World
++ EL0                                           |
++                                               |
++ EL1                           BL32(Tee OS)    |     kernel
++                                ^ |            |       ^
++                                | |            |       |
++ EL2                            | |            |     BL33(u-boot)
++                                | |            |      ^
++                                | v            |     /
++ EL3        BootROM --> BL2 --> BL31 ---------------/
++
+
+Boot Sequence with FIP-DDR
+--------------------------
+::
+
++                           Secure World        |     Normal World
++ EL0                                           |
++                                               |
++ EL1               fip-ddr     BL32(Tee OS)    |     kernel
++                     ^ |         ^ |           |       ^
++                     | |         | |           |       |
++ EL2                 | |         | |           |     BL33(u-boot)
++                     | |         | |           |      ^
++                     | v         | v           |     /
++ EL3     BootROM --> BL2 -----> BL31 ---------------/
++
+
+
+How to build
+=============
+
+Code Locations
+--------------
+
+-  OP-TEE:
+   `link <https://source.codeaurora.org/external/qoriq/qoriq-components/optee_os>`__
+
+-  U-Boot:
+   `link <https://source.codeaurora.org/external/qoriq/qoriq-components/u-boot>`__
+
+-  RCW:
+   `link <https://source.codeaurora.org/external/qoriq/qoriq-components/rcw>`__
+
+-  ddr-phy-binary: Required by platforms that need fip-ddr.
+   `link <https:://github.com/NXP/ddr-phy-binary>`__
+
+-  cst: Required for TBBR.
+   `link <https:://source.codeaurora.org/external/qoriq/qoriq-components/cst>`__
+
+Build Procedure
+---------------
+
+-  Fetch all the above repositories into local host.
+
+-  Prepare AARCH64 toolchain and set the environment variable "CROSS_COMPILE".
+
+   .. code:: shell
+
+       export CROSS_COMPILE=.../bin/aarch64-linux-gnu-
+
+-  Build RCW. Refer README from the respective cloned folder for more details.
+
+-  Build u-boot and OPTee firstly, and get binary images: u-boot.bin and tee.bin.
+   For u-boot you can use the <platform>_tfa_defconfig for build.
+
+-  Copy/clone the repo "ddr-phy-binary" to the tfa directory for platform needing ddr-fip.
+
+-  Below are the steps to build TF-A images for the supported platforms.
+
+Compilation steps without BL32
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+BUILD BL2:
+
+-To compile
+   .. code:: shell
+
+       make PLAT=$PLAT \
+       BOOT_MODE=<platform_supported_boot_mode> \
+       RCW=$RCW_BIN \
+       pbl
+
+BUILD FIP:
+
+   .. code:: shell
+
+       make PLAT=$PLAT \
+       BOOT_MODE=<platform_supported_boot_mode> \
+       RCW=$RCW_BIN \
+       BL33=$UBOOT_SECURE_BIN \
+       pbl \
+       fip
+
+Compilation steps with BL32
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+BUILD BL2:
+
+-To compile
+   .. code:: shell
+
+       make PLAT=$PLAT \
+       BOOT_MODE=<platform_supported_boot_mode> \
+       RCW=$RCW_BIN \
+       BL32=$TEE_BIN SPD=opteed\
+       pbl
+
+BUILD FIP:
+
+   .. code:: shell
+
+       make PLAT=$PLAT \
+       BOOT_MODE=<platform_supported_boot_mode> \
+       RCW=$RCW_BIN \
+       BL32=$TEE_BIN SPD=opteed\
+       BL33=$UBOOT_SECURE_BIN \
+       pbl \
+       fip
+
+
+BUILD fip-ddr (Mandatory for certain platforms, refer table above):
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+-To compile additional fip-ddr for selected platforms(Refer above table if the platform needs fip-ddr).
+   .. code:: shell
+
+	make PLAT=<platform_name> fip-ddr
+
+
+Deploy ATF Images
+=================
+
+Note: The size in the standard uboot commands for copy to nor, qspi, nand or sd
+should be modified based on the binary size of the image to be copied.
+
+-  Deploy ATF images on flexspi-Nor flash Alt Bank from U-Boot prompt.
+   --  Commands to flash images for bl2_xxx.pbl and fip.bin.
+
+   .. code:: shell
+
+        tftp 82000000  $path/bl2_flexspi_nor.pbl;
+        i2c mw 66 50 20;sf probe 0:0; sf erase 0 +$filesize; sf write 0x82000000 0x0 $filesize;
+
+        tftp 82000000  $path/fip.bin;
+        i2c mw 66 50 20;sf probe 0:0; sf erase 0x100000 +$filesize; sf write 0x82000000 0x100000 $filesize;
+
+   --  Next step is valid for platform where FIP-DDR is needed.
+
+   .. code:: shell
+
+        tftp 82000000  $path/ddr_fip.bin;
+        i2c mw 66 50 20;sf probe 0:0; sf erase 0x800000 +$filesize; sf write 0x82000000 0x800000 $filesize;
+
+   --  Then reset to alternate bank to boot up ATF.
+
+   .. code:: shell
+
+        qixisreset altbank;
+
+-  Deploy ATF images on SD/eMMC from U-Boot prompt.
+   -- file_size_in_block_sizeof_512 = (Size_of_bytes_tftp / 512)
+
+   .. code:: shell
+
+        mmc dev <idx>; (idx = 1 for eMMC; idx = 0 for SD)
+
+        tftp 82000000  $path/bl2_<sd>_or_<emmc>.pbl;
+        mmc write 82000000 8 <file_size_in_block_sizeof_512>;
+
+        tftp 82000000  $path/fip.bin;
+        mmc write 82000000 0x800 <file_size_in_block_sizeof_512>;
+
+    --  Next step is valid for platform that needs FIP-DDR.
+
+   .. code:: shell
+
+        tftp 82000000  $path/ddr_fip.bin;
+        mmc write 82000000 0x4000 <file_size_in_block_sizeof_512>;
+
+   --  Then reset to sd/emmc to boot up ATF from sd/emmc as boot-source.
+
+   .. code:: shell
+
+        qixisreset <sd or emmc>;
+
+Trusted Board Boot:
+===================
+
+For TBBR, the binary name changes:
+
++-------------+--------------------------+---------+-------------------+
+|  Boot Type  |           BL2            |   FIP   |      FIP-DDR      |
++=============+==========================+=========+===================+
+| Normal Boot |  bl2_<boot_mode>.pbl     | fip.bin | ddr_fip.bin       |
++-------------+--------------------------+---------+-------------------+
+| TBBR Boot   |  bl2_<boot_mode>_sec.pbl | fip.bin | ddr_fip_sec.bin   |
++-------------+--------------------------+---------+-------------------+
+
+Refer `nxp-ls-tbbr.rst`_ for detailed user steps.
+
+
+.. _lx2160ardb: https://www.nxp.com/products/processors-and-microcontrollers/arm-processors/layerscape-communication-process/layerscape-lx2160a-multicore-communications-processor:LX2160A
+.. _nxp-ls-tbbr.rst: ./nxp-ls-tbbr.rst
diff --git a/docs/plat/nxp/nxp-ls-fuse-prov.rst b/docs/plat/nxp/nxp-ls-fuse-prov.rst
new file mode 100644
index 000000000..64e1c6f8c
--- /dev/null
+++ b/docs/plat/nxp/nxp-ls-fuse-prov.rst
@@ -0,0 +1,271 @@
+
+Steps to blow fuses on NXP LS SoC:
+==================================
+
+
+- Enable POVDD
+  -- Refer board GSG(Getting Started Guide) for the steps to enable POVDD.
+  -- Once the POVDD is enabled, make sure to set variable POVDD_ENABLE := yes, in the platform.mk.
+
++---+-----------------+-----------+------------+-----------------+-----------------------------+
+|   |   Platform      |  Jumper   |  Switch    | LED to Verify   |  Through GPIO Pin (=number) |
++===+=================+===========+============+=================+=============================+
+| 1.| lx2160ardb      |  J9       |            |                 |             no              |
++---+-----------------+-----------+------------+-----------------+-----------------------------+
+| 2.| lx2160aqds      |  J35      |            |                 |             no              |
++---+-----------------+-----------+------------+-----------------+-----------------------------+
+| 3.| lx2162aqds      |  J35      | SW9[4] = 1 |    D15          |             no              |
++---+-----------------+-----------+------------+-----------------+-----------------------------+
+
+- SFP registers to be written to:
+
++---+----------------------------------+----------------------+----------------------+
+|   |   Platform                       |   OTPMKR0..OTPMKR7   |   SRKHR0..SRKHR7     |
++===+==================================+======================+======================+
+| 1.| lx2160ardb/lx2160aqds/lx2162aqds | 0x1e80234..0x1e80250 | 0x1e80254..0x1e80270 |
++---+----------------------------------+----------------------+----------------------+
+
+- At U-Boot prompt, verify that SNVS register - HPSR, whether OTPMK was written, already:
+
++---+----------------------------------+-------------------------------------------+---------------+
+|   |   Platform                       |           OTPMK_ZERO_BIT(=value)          | SNVS_HPSR_REG |
++===+==================================+===========================================+===============+
+| 1.| lx2160ardb/lx2160aqds/lx2162aqds | 27 (= 1 means not blown, =0 means blown)  | 0x01E90014    |
++---+----------------------------------+-------------------------------------------+---------------+
+
+From u-boot prompt:
+
+  --  Check for the OTPMK.
+   .. code:: shell
+
+        md $SNVS_HPSR_REG
+
+      Command Output:
+          01e90014: 88000900
+
+          In case it is read as 00000000, then read this register using jtag (in development mode only through CW tap).
+                       +0       +4       +8       +C
+          [0x01E90014] 88000900
+
+          Note: OTPMK_ZERO_BIT is 1, indicating that the OTPMK is not blown.
+
+  --  Check for the SRK Hash.
+   .. code:: shell
+
+        md $SRKHR0 0x10
+
+      Command Output:
+          01e80254: 00000000 00000000 00000000 00000000    ................
+          01e80264: 00000000 00000000 00000000 00000000    ................
+
+          Note: Zero means that SRK hash is not blown.
+
+- If not blown, then from the U-Boot prompt, using following commands:
+  --  Provision the OTPMK.
+
+   .. code:: shell
+
+        mw.l $OTPMKR0  <OTMPKR_0_32Bit_val>
+        mw.l $OTPMKR1  <OTMPKR_1_32Bit_val>
+        mw.l $OTPMKR2  <OTMPKR_2_32Bit_val>
+        mw.l $OTPMKR3  <OTMPKR_3_32Bit_val>
+        mw.l $OTPMKR4  <OTMPKR_4_32Bit_val>
+        mw.l $OTPMKR5  <OTMPKR_5_32Bit_val>
+        mw.l $OTPMKR6  <OTMPKR_6_32Bit_val>
+        mw.l $OTPMKR7  <OTMPKR_7_32Bit_val>
+
+  --  Provision the SRK Hash.
+
+   .. code:: shell
+
+        mw.l $SRKHR0  <SRKHR_0_32Bit_val>
+        mw.l $SRKHR1  <SRKHR_1_32Bit_val>
+        mw.l $SRKHR2  <SRKHR_2_32Bit_val>
+        mw.l $SRKHR3  <SRKHR_3_32Bit_val>
+        mw.l $SRKHR4  <SRKHR_4_32Bit_val>
+        mw.l $SRKHR5  <SRKHR_5_32Bit_val>
+        mw.l $SRKHR6  <SRKHR_6_32Bit_val>
+        mw.l $SRKHR7  <SRKHR_7_32Bit_val>
+
+      Note: SRK Hash should be carefully written keeping in mind the SFP Block Endianness.
+
+- At U-Boot prompt, verify that SNVS registers for OTPMK are correctly written:
+
+  --  Check for the OTPMK.
+   .. code:: shell
+
+        md $SNVS_HPSR_REG
+
+      Command Output:
+          01e90014: 80000900
+
+          OTPMK_ZERO_BIT is zero, indicating that the OTPMK is blown.
+
+          Note: In case it is read as 00000000, then read this register using jtag (in development mode only through CW tap).
+
+   .. code:: shell
+
+        md $OTPMKR0 0x10
+
+      Command Output:
+          01e80234: ffffffff ffffffff ffffffff ffffffff    ................
+          01e80244: ffffffff ffffffff ffffffff ffffffff    ................
+
+          Note: OTPMK will never be visible in plain.
+
+  --  Check for the SRK Hash. For example, if following SRK hash is written:
+
+       SFP SRKHR0 = fdc2fed4
+       SFP SRKHR1 = 317f569e
+       SFP SRKHR2 = 1828425c
+       SFP SRKHR3 = e87b5cfd
+       SFP SRKHR4 = 34beab8f
+       SFP SRKHR5 = df792a70
+       SFP SRKHR6 = 2dff85e1
+       SFP SRKHR7 = 32a29687,
+
+       then following would be the value on dumping SRK hash.
+
+   .. code:: shell
+
+        md $SRKHR0 0x10
+
+      Command Output:
+          01e80254: d4fec2fd 9e567f31 5c422818 fd5c7be8    ....1.V..(B\.{\.
+          01e80264: 8fabbe34 702a79df e185ff2d 8796a232    4....y*p-...2...
+
+          Note: SRK Hash is visible in plain based on the SFP Block Endianness.
+
+- Caution: Donot proceed to the next step, until you are sure that OTPMK and SRKH are correctly blown from above steps.
+  -- After the next step, there is no turning back.
+  -- Fuses will be burnt, which cannot be undo.
+
+- Write SFP_INGR[INST] with the PROGFB(0x2) instruction to blow the fuses.
+  -- User need to save the SRK key pair and OTPMK Key forever, to continue using this board.
+
++---+----------------------------------+-------------------------------------------+-----------+
+|   |   Platform                       | SFP_INGR_REG | SFP_WRITE_DATE_FRM_MIRROR_REG_TO_FUSE  |
++===+==================================+=======================================================+
+| 1.| lx2160ardb/lx2160aqds/lx2162aqds | 0x01E80020   |    0x2                                 |
++---+----------------------------------+--------------+----------------------------------------+
+
+   .. code:: shell
+
+        md $SFP_INGR_REG  $SFP_WRITE_DATE_FRM_MIRROR_REG_TO_FUSE
+
+- On reset, if the SFP register were read from u-boot, it will show the following:
+  --  Check for the OTPMK.
+
+   .. code:: shell
+
+        md $SNVS_HPSR_REG
+
+      Command Output:
+          01e90014: 80000900
+
+          In case it is read as 00000000, then read this register using jtag (in development mode only through CW tap).
+                       +0       +4       +8       +C
+          [0x01E90014] 80000900
+
+          Note: OTPMK_ZERO_BIT is zero, indicating that the OTPMK is blown.
+
+   .. code:: shell
+
+        md $OTPMKR0 0x10
+
+      Command Output:
+          01e80234: ffffffff ffffffff ffffffff ffffffff    ................
+          01e80244: ffffffff ffffffff ffffffff ffffffff    ................
+
+          Note: OTPMK will never be visible in plain.
+
+  -- SRK Hash
+
+   .. code:: shell
+
+        md $SRKHR0 0x10
+
+      Command Output:
+          01e80254: d4fec2fd 9e567f31 5c422818 fd5c7be8    ....1.V..(B\.{\.
+          01e80264: 8fabbe34 702a79df e185ff2d 8796a232    4....y*p-...2...
+
+          Note: SRK Hash is visible in plain based on the SFP Block Endianness.
+
+Second method to do the fuse provsioning:
+=========================================
+
+This method is used for quick way to provision fuses.
+Typically used by those who needs to provision number of boards.
+
+- Enable POVDD:
+  -- Refer the table above to enable POVDD.
+
+     Note: If GPIO Pin supports enabling POVDD, it can be done through the below input_fuse_file.
+
+  -- Once the POVDD is enabled, make sure to set variable POVDD_ENABLE := yes, in the platform.mk.
+
+- User need to populate the "input_fuse_file", corresponding to the platform for:
+
+  -- OTPMK
+  -- SRKH
+
+  Table of fuse provisioning input file for every supported platform:
+
++---+----------------------------------+-----------------------------------------------------------------+
+|   |   Platform                       |                        FUSE_PROV_FILE                           |
++===+==================================+=================================================================+
+| 1.| lx2160ardb/lx2160aqds/lx2162aqds | ${CST_DIR}/input_files/gen_fusescr/ls2088_1088/input_fuse_file  |
++---+----------------------------------+--------------+--------------------------------------------------+
+
+- Create the TF-A binary with FUSE_PROG=1.
+
+   .. code:: shell
+
+        make PLAT=$PLAT FUSE_PROG=1\
+          BOOT_MODE=<platform_supported_boot_mode> \
+          RCW=$RCW_BIN \
+          BL32=$TEE_BIN SPD=opteed\
+          BL33=$UBOOT_SECURE_BIN \
+          pbl \
+          fip \
+          fip_fuse \
+          FUSE_PROV_FILE=../../apps/security/cst/input_files/gen_fusescr/ls2088_1088/input_fuse_file
+
+- Deployment:
+  -- Refer the nxp-layerscape.rst for deploying TF-A images.
+  -- Deploying fip_fuse.bin:
+
+       For Flexspi-Nor:
+
+   .. code:: shell
+
+        tftp 82000000  $path/fuse_fip.bin;
+        i2c mw 66 50 20;sf probe 0:0; sf erase 0x880000 +$filesize; sf write 0x82000000 0x880000 $filesize;
+
+      For SD or eMMC [file_size_in_block_sizeof_512 = (Size_of_bytes_tftp / 512)]:
+
+   .. code:: shell
+
+        tftp 82000000  $path/fuse_fip.bin;
+        mmc write 82000000 0x4408 <file_size_in_block_sizeof_512>;
+
+- Valiation:
+
++---+----------------------------------+---------------------------------------------------+
+|   |   Platform                       |    Error_Register        | Error_Register_Address |
++===+==================================+===================================================+
+| 1.| lx2160ardb/lx2160aqds/lx2162aqds | DCFG scratch 4 register  |     0x01EE020C         |
++---+----------------------------------+---------------------------------------------------+
+
+   At the U-Boot prompt, check DCFG scratch 4 register for any error.
+
+   .. code:: shell
+
+        md $Error_Register_Address 1
+
+      Command Ouput:
+          01ee020c: 00000000
+
+      Note:
+       - 0x00000000 shows no error, then fuse provisioning is successful.
+       - For non-zero value, refer the code header file ".../drivers/nxp/sfp/sfp_error_codes.h"
diff --git a/docs/plat/nxp/nxp-ls-tbbr.rst b/docs/plat/nxp/nxp-ls-tbbr.rst
new file mode 100644
index 000000000..43e15f7ef
--- /dev/null
+++ b/docs/plat/nxp/nxp-ls-tbbr.rst
@@ -0,0 +1,210 @@
+
+--------------
+NXP Platforms:
+--------------
+TRUSTED_BOARD_BOOT option can be enabled by specifying TRUSTED_BOARD_BOOT=1 on command line during make.
+
+
+
+Bare-Minimum Preparation to run  TBBR on NXP Platforms:
+=======================================================
+- OTPMK(One Time Programable Key) needs to be burnt in fuses.
+  -- It is the 256 bit key that stores a secret value used by the NXP SEC 4.0 IP in Trusted or Secure mode.
+
+     Note: It is primarily for the purpose of decrypting additional secrets stored in system non-volatile memory.
+
+  -- NXP CST tool gives an option to generate it.
+
+   Use the below command from directory 'cst', with correct options.
+
+   .. code:: shell
+
+     ./gen_otpmk_drbg
+
+- SRKH (Super Root Key Hash) needs to be burnt in fuses.
+  -- It is the 256 bit hash of the list of the public keys of the SRK key pair.
+  -- NXP CST tool gives an option to generate the RSA key pair and its hash.
+
+   Use the below command from directory 'cst', with correct options.
+
+   .. code:: shell
+
+     ./gen_keys
+
+Refer fuse frovisioning readme 'nxp-ls-fuse-prov.rst' for steps to blow these keys.
+
+
+
+Two options are provided for TRUSTED_BOARD_BOOT:
+================================================
+
+-------------------------------------------------------------------------
+Option 1: CoT using X 509 certificates
+-------------------------------------------------------------------------
+
+- This CoT is as provided by ARM.
+
+- To use this option user needs to specify mbedtld dir path in MBEDTLS_DIR.
+
+- To generate CSF header, path of CST repository needs to be specified as CST_DIR
+
+- CSF header is embedded to each of the BL2 image.
+
+- GENERATE_COT=1 adds the tool 'cert_create' to the build environment to generate:
+  -- X509 Certificates as (.crt) files.
+  -- X509 Pem key file as (.pem) files.
+
+- SAVE_KEYS=1 saves the keys and certificates, if GENERATE_COT=1.
+  -- For this to work, file name for cert and keys are provided as part of  compilation or build command.
+
+     --- default file names will be used, incase not provided as part compilation or build command.
+     --- default folder 'BUILD_PLAT' will be used to store them.
+
+- ROTPK for x.509 certificates is generated and embedded in bl2.bin and
+  verified as part of CoT by Boot ROM during secure boot.
+
+- Compilation steps:
+
+All Images
+   .. code:: shell
+
+       make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 GENERATE_COT=1 MBEDTLS_DIR=$MBEDTLS_PATH CST_DIR=$CST_DIR_PATH \
+       BOOT_MODE=<platform_supported_boot_mode> \
+       RCW=$RCW_BIN \
+       BL32=$TEE_BIN SPD=opteed\
+       BL33=$UBOOT_SECURE_BIN \
+       pbl \
+       fip
+
+Additional FIP_DDR Image (For NXP platforms like lx2160a)
+   .. code:: shell
+
+       make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 GENERATE_COT=1 MBEDTLS_DIR=$MBEDTLS_PATH fip_ddr
+
+      Note: make target 'fip_ddr' should never be combine with other make target 'fip', 'pbl' & 'bl2'.
+
+-------------------------------------------------------------------------
+Option 2: CoT using NXP CSF headers.
+-------------------------------------------------------------------------
+
+- This option is automatically selected when TRUSTED_BOARD_BOOT is set but MBEDTLS_DIR path is not specified.
+
+- CSF header is embedded to each of the BL31, BL32 and  BL33 image.
+
+- To generate CSF header, path of CST repository needs to be specified as CST_DIR
+
+- Default input files for CSF header generation is added in this repo.
+
+- Default input file requires user to generate RSA key pair named
+  -- srk.pri, and
+  -- srk.pub, and add them in ATF repo.
+  -- These keys can be generated using gen_keys tool of CST.
+
+- To change the input file , user can use the options BL33_INPUT_FILE, BL32_INPUT_FILE, BL31_INPUT_FILE
+
+- There are 2 paths in secure boot flow :
+  -- Development Mode (sb_en in RCW = 1, SFP->OSPR, ITS = 0)
+
+     --- In this flow , even on ROTPK comparison failure, flow would continue.
+     --- However SNVS is transitioned to non-secure state
+
+  -- Production mode (SFP->OSPR, ITS = 1)
+
+     --- Any failure is fatal failure
+
+- Compilation steps:
+
+All Images
+   .. code:: shell
+
+       make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 CST_DIR=$CST_DIR_PATH \
+       BOOT_MODE=<platform_supported_boot_mode> \
+       RCW=$RCW_BIN \
+       BL32=$TEE_BIN SPD=opteed\
+       BL33=$UBOOT_SECURE_BIN \
+       pbl \
+       fip
+
+Additional FIP_DDR Image (For NXP platforms like lx2160a)
+   .. code:: shell
+
+       make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 CST_DIR=$CST_DIR_PATH fip_ddr
+
+- Compilation Steps with build option for generic image processing filters to prepend CSF header:
+  --  Generic image processing filters to prepend CSF header
+
+      BL32_INPUT_FILE = < file name>
+      BL33_INPUT_FILE = <file name>
+
+   .. code:: shell
+
+       make PLAT=$PLAT TRUSTED_BOARD_BOOT=1 CST_DIR=$CST_DIR_PATH \
+       BOOT_MODE=<platform_supported_boot_mode> \
+       RCW=$RCW_BIN \
+       BL32=$TEE_BIN SPD=opteed\
+       BL33=$UBOOT_SECURE_BIN \
+       BL33_INPUT_FILE = <ip file> \
+       BL32_INPUT_FILE = <ip_file> \
+       BL31_INPUT_FILE = <ip file> \
+       pbl \
+       fip
+
+
+Deploy ATF Images
+=================
+Same steps as mentioned in the readme "nxp-layerscape.rst".
+
+
+
+Verification to check if Secure state is achieved:
+==================================================
+
++---+----------------+-----------------+------------------------+----------------------------------+-------------------------------+
+|   |   Platform     |  SNVS_HPSR_REG  | SYS_SECURE_BIT(=value) | SYSTEM_SECURE_CONFIG_BIT(=value) | SSM_STATE                     |
++===+================+=================+========================+==================================+===============================+
+| 1.| lx2160ardb  or |    0x01E90014   | 15                     | 14-12                            | 11-8                          |
+|   | lx2160aqds  or |                 | ( = 1, BootROM Booted) | ( = 010 means Intent to Secure,  | (=1111 means secure boot)     |
+|   | lx2162aqds     |                 |                        | ( = 000 Unsecure)                | (=1011 means Non-secure Boot) |
++---+----------------+-----------------+------------------------+----------------------------------+-------------------------------+
+
+- Production mode (SFP->OSPR, ITS = 1)
+  -- Linux prompt will successfully come. if the TBBR is successful.
+
+     --- Else, Linux boot will be successful.
+
+  -- For secure-boot status, read SNVS Register $SNVS_HPSR_REG from u-boot prompt:
+
+   .. code:: shell
+
+        md $SNVS_HPSR_REG
+
+      Command Output:
+          1e90014: 8000AF00
+
+          In case it is read as 00000000, then read this register using jtag (in development mode only through CW tap).
+                       +0       +4       +8       +C
+          [0x01E90014] 8000AF00
+
+
+- Development Mode (sb_en in RCW = 1, SFP->OSPR, ITS = 0)
+  -- Refer the SoC specific table to read the register to interpret whether the secure boot is achieved or not.
+  -- Using JTAG (in development environment only, using CW tap):
+
+     --- For secure-boot status, read SNVS Register $SNVS_HPSR_REG
+
+   .. code:: shell
+
+        ccs::display_regs 86 0x01E90014 4 0 1
+
+      Command Output:
+          Using the SAP chain position number 86, following is the output.
+
+                       +0       +4       +8       +C
+          [0x01E90014] 8000AF00
+
+          Note: Chain position number will vary from one SoC to other SoC.
+
+- Interpretation of the value:
+
+  -- 0xA indicates BootROM booted, with intent to secure.
+  -- 0xF = secure boot, as SSM_STATE.